gnu: python-flask-basicauth: Fix build.

* gnu/packages/python-web.scm (python-flask-basicauth)[phases]: Add a
'fix-imports phase.

gnu/packages/python-web.scm

@@ -26,7 +26,7 @@
 ;;; Copyright © 2018 Tomáš Čech <sleep_walker@gnu.org>
 ;;; Copyright © 2018, 2019 Nicolas Goaziou <mail@nicolasgoaziou.fr>
 ;;; Copyright © 2018 Mathieu Othacehe <m.othacehe@gmail.com>
-;;; Copyright © 2018 Maxim Cournoyer <maxim.cournoyer@gmail.com>
+;;; Copyright © 2018, 2020 Maxim Cournoyer <maxim.cournoyer@gmail.com>
 ;;; Copyright © 2019 Vagrant Cascadian <vagrant@debian.org>
 ;;; Copyright © 2019 Brendan Tildesley <mail@brendan.scot>
 ;;; Copyright © 2019 Pierre Langlois <pierre.langlois@gmx.com>
@@ -2895,6 +2895,17 @@ pretty printer and a tree visitor.")
           (base32
             "1zq1spkjr4sjdnalpp8wl242kdqyk6fhbnhr8hi4r4f0km4bspnz"))))
     (build-system python-build-system)
+    (arguments
+     `(#:phases (modify-phases %standard-phases
+                  (add-after 'unpack 'fix-imports
+                    (lambda _
+                      (substitute* '("docs/index.rst"
+                                     "docs/conf.py"
+                                     "flask_basicauth.py"
+                                     "test_basicauth.py")
+                        (("flask\\.ext\\.basicauth")
+                         "flask_basicauth"))
+                      #t)))))
     (propagated-inputs
      `(("python-flask" ,python-flask)))
     (home-page